“It’s a very funny relationship that the two of them have: First of all, it’s the biggest superhero and the smallest. Just keeping them in a frame together is a feat and hilarious in itself,” Ruffalo told USA Today.

“All of the universes coming together is just a sight gag within itself.”

The relationship was originally expected to surface during last year’s Avengers: Infinity War.

We now know Hulk and Rocket become friendly come Avengers: Endgame, after the two were last seen in Wakanda among some of the last remaining heroes who survived Thanos’ (Josh Brolin) snap that obliterated half of all life in the universe.

The only other surviving member of the Guardians, Nebula (Karen Gillan), will forge a new friendship of her own with Tony Stark (Robert Downey Jr). She was stranded with the armored Avenger on the decimated planet of Titan after their botched attack on Thanos.

Gillan told Fandango in August 2017 Nebula gets a “new BFF,” another relationship initially expected to surface during Infinity War.

“I can’t tell you. I can’t,” she said at the time. “I promise you it’s brilliant and unexpected and just so good.”

Both Avengers films were shot back-to-back, causing its stars — many of whom did not receive scripts, Gillan included — to inadvertently let slip Endgame details when promoting Infinity War.

Ruffalo, before returning for reshoots in September, admitted its stars “don’t even know what it’s gonna be yet,” referring to the project then known only as ‘Avengers 4.’

The Hulk star added he was unsure if even its creative team — directors Anthony and Joe Russo, and screenwriters Stephen McFeely and Christopher Markus — knew what the finalized film would look like as it was being remolded.

“I don’t even know that they really know exactly," Ruffalo said.

“Some of it is happening while we’re there. It’s pretty amazing. And we’ll shoot some stuff and a few days later come back and reshoot it cause we wanna take it in another direction. It’s a very living organism, even as we approach it being a locked picture, we’re still working on it.”

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